2.1.1 microscopes Flashcards
how are cells prepared in a lab (6)
- tissue fixation + processing in formaldehyde
• dehydration of specimens to remove water
• embedding in wax to avoid distortion
• section-cutting using special instrument to make very small, THIN slices (to maximise light that can penetrate)
• staining (add stain at the edge of the slide)
• add coverslip - try to avoid air bubbles.
how do you calculate magnification?
image size / actual size
what is the magnification of a light microscope?
- up to x1500
what is the resolution of a light microscope?
200 nanometres
what is the magnification of a laser scanning confocal microscope?
up to x1500
what is the resolution of a laser scanning confocal microscope?
10 nanometres
what’s the resolution of a scanning electron microscope?
between 0.2 and 10 nanometres
what’s the magnification of the scanning electron microscope?
x15000 to x20000
what type of images are produced by light microscopes?
- 2D images
- coloured images
what type of images are produced by laser scanning microscopes?
- 3D images
- colour
what type of images are made by transmission electron microscopes? (2)
- 2D images
- black and white images
what type of images are created by scanning electron microscopes?
- 3D images
what’s the definition of magnification?
- how many times larger an object is compared to its actual size
what’s the definition of resolution?
- the ability to distinguish two points in close proximity as seperate.
what is the difference between magnification and resolution?
why do we use differential staining in microscopy?
to distinguish between different cellular components and different cell types
